Method and apparatus for manufacture of and improvements in explosive transfer link

ABSTRACT

An explosive transfer link is designed to the assembled by a novel method which eliminates hazards inherent in prior production. The high energy booster charges at each end are not placed in position until final assembly. The charges are then press loaded by remote control.

United States Patent [191 Johnson et ai.

METHOD AND APPARATUS FOR MANUFACTURE OF AND IMPROVEMENTS IN EXPLOSIVE TRANSFER LINK Inventors: Clifford T. Johnson; Herbert M.

Neuhaus, both of China Lake; Wallace E. Silver, Ridgecrest; Gordon D. Whiting, China Lake; Richard A. N. Larson, Agoura, all of Calif.

Assignee: The United States of America as represented by the Secretary of the Navy Filed: Aug. 31, 1970 Appl. No.: 68,582

u.s. Cl. ..86/22, 86/31, 102/27 Int. Cl ..C06d 1/08, F42b 3/10 Field of Search ..86/22, 30, 31, 32, l; 102/27 1 Jan. 30, 1973 [56] References Cited UNITED STATES PATENTS 3,464,3ll 9/1969 Smith ..86/l R 1,688,!22 l0/l928 McLean ..86/22 3,136,83l 6/1964 Zinn ..86/l R X 2,345,552 4/1944 Balloa ..86/30 Primary ExaminerBenjamin A. Borchelt Assistant Examiner--Harold Tudor Attorney-Richard S. Sciascia, Roy Miller and Gerald F. Baker [57] ABSTRACT An explosive transfer link is designed to the assembled by a novel method which eliminates hazards inherent in prior production. The high energy booster charges at each end are not placed in position until final assembly. The charges are then press loaded by remote control.

2 Claims, 13 Drawing Figures PATENTEDJAH30 I975 3.713361 n-m-n-q FIG. 4

INVENTORS CLIFFORD Z JOHNSON HERBERT M. IVEUHAUS WALLACE E. SILVER 3 GORDON D. WH/TING RICHARD A. LARSON GERALQ Q QAKER SHEET 2 BF 4 v 4 b m n Q F a 9 m a 5 W F PATENTEDJAI 30 I975 FIG. 8

FIG: 6

PATENTEDJAN 30 ms SHEET 3 [1F 4 FIG. 9

PATENTEDJAN 30 I978 SHEET l [1F 4 FIG.

METHOD AND APPARATUS FOR MANUFACTURE OF AND IMPROVEMENTS IN EXPLOSIVE TRANSFER LINK CROSS REFERENCE TO RELATED APPLICATION This application relates to an invention involving an initiation transfer link similar to that disclosed in assignees copending application Ser. No. 753,215 filed Aug. I6, 1968 for a warhead initiation transfer link.

BACKGROUND OF THE INVENTION In certain weapon systems it is desirable to detonate an explosive at an area remote from the initiation. One way of accomplishing this result is to put a train of explosive cord between the initiator and the area of detonation. Such cords have become known as explosive transfer trains or detonation transfer cords.

In the manufacture of prior transfer trains a booster cup containing high energy explosive was attached to each end of a mild detonating cord by hand. The assembly was then fitted with end pieces as needed for the particular use. The placing of the high energy explosive on either end of the cord, however, proved to be very hazardous and better methods of assembly were sought.

According to the present invention, a mild detonating cord is provided with acceptor and donor end pieces which have cavities for a high explosive and the cavities are filled with the high explosive only at final assembly and by remote means.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a longitudinal cross sectional view of a detonating cord according to a prior design;

FIG. 2 is a longitudinal cross sectional view of a transfer link according to the present invention;

FIG. 3 is a top plan view of a split die for use in practicing the present invention;

FIG. 4 is an end view of the split die of FIG. 3;

FIG. 5 is a top plan view of a stand-off fixture for use with the die of FIG. 3;

FIG. 6 is a cross sectional view of the fixture of FIG. 5;

FIG. 7a is a top view of a split adapter for use with the die of FIG. 3;

FIG. 7b is a longitudinal cross sectional view of the adapter of FIG. 7a;

FIG. 8 is a side view of a punch usable with the adapter of FIG. 7a;

FIG. 9 is a cross sectional view of the die and fixture combination with the adapter and detonating cord in place;

FIG. 10 is a perspective view of the arrangement of FIG. 9;

FIG. 11 is a perspective view similar to FIG. I0 showing the punch in place; and

FIG. 12 is an exploded view of the parts making up v the loading fixture of FIG. 9.

DESCRIPTION OF THE INVENTION The assembly designated by the numeral 10 in FIG. I is an example of a prior art confined detonating cord transfer train. Assembly of the train begins with a length of mild detonating fuse (MDF) which is commercially available in a variety of :forms and with a powder .content specified in grains per running .foot. The 'MDF 12 shown in FIGS. I and 2 consists of a woven cotton sheath 1'3 filled with powder 18 and provided with aiead covering 14.

In the train assemblies shown, the MDF 12 has been covered with a glass fiber material '15 and a coating of plastic material '16.

To adapt-the cord further to aparticular detonation train, end pieces such as'20 and 30 are necessary. -In the FIG. 1 device these end pieces 20, 30 .are fastened to the cord by .the intermediate ferrules 22, 32. Each of the ferrules is fitted with an end cup 26-containing.an

explosive mixture 28 which is more sensitive and powerful than the mixture 18 in .the detonating cord 12. Each :of the adapter ferrules 22, 32 are relieved to receive end cups 26 and the ferrule 32 is further relieved to accommodate atransition-piece 33.

In this construction, after the cups 26 have been slipped onto the ends of the ferrules 22, 32, they are hand crimped .to the ferrules as shown at 27. Finally, the end pieces 20, 30 are fastened onto the respective ferrules. Receptor end 20, which is at. the initiating end of the cord, is shown provided with a threaded portion and a head for the purpose of fastening the train into place.

I-Iand placement of the prepared end cups 26 onto the ferrules has been a hazardous operation, performed in'hand operated crimping devices, and the entire cord was hazardous to handle and store after the placement of the explosive. In addition, the placement of the final end pieces 20, 30 was also a hazardous manual operation.

The improved design is shown at 10' in FIG. 2 wherein the detonating cord 12 is fastened directly into modified end pieces 20 and 30. These modified end pieces are provided with cup shaped counterbores 40, 70 respectively for the reception of the explosive mixture 28. The explosive mixture, however, is not placed until the final step in preparing the train for use. After the explosive mixture 28 has been placed the mixture is covered with a thin plate 42 which fits into recesses 41, 5 I provided in the respective end pieces.

In comparison of the FIG. 2 device to the FIG. 1 device, it is apparent that several separate items have been eliminated. The elimination of these items and the concurrent elimination of several hazardous assembly steps has resulted in a much safer assembly.

The safer and more reliable detonating cord assembly of FIG. 2 was made possible by the invention of a novel method of placing the explosive charges and the invention of apparatus for performing that method. The method involves the press loading of the explosive mix 28 after the end pieces 20', 30 have been secured to the detonating cord 12. The press loading of the end pieces is accomplished by means of a split die as shown in FIGS. 3 and 4. The die comprises two half die portions 71, 72 fastened together by a hinge 73 which may be bolted thereon as by bolts 75. The halves of the die may be closed by any means such as the latch, 76. Shown in the die of FIG. 3 is an adapter comprising two halves 90, 90' the use of which will be more fully explained in the description of later Figures.

FIGS. 5 and 6 illustrate a stand or fixture upon which the die 70 is placed to provide a stand-off in the pressing operation as will become apparent in discussing FIG. 9. The fixture 80 comprises generally a metal cylinder 81 topped by a metal plate 83 which is relieved at 84 to receive the bottom of die 70. The adapter shown in FIGS. 7a and 7b is designed to confine the end piece 30 in the die as shown in FIGS. 9 and 10 after which the plunger 92 (FIG. 8) is placed as shown in FIG. 1. The assembly as shown in FIG. 11 is placed on a press bed and the top platen of the press is brought down to bear on the head of plunger )2. Actual pressing of the explosive is then carried out by remote control.

The only remaining step is to place the cover pieces 42. These covers 42 may be fastened in place by any known means but are typically fastened by deforming the material around the periphery of recesses 41, 51 respectively by a rolling process, also carried out by remote control.

Since the explosive material is placed as a final step in the process of manufacture, all intervening assembly operations have been rendered much less hazardous and the placement of the explosive by remote control makes this final step much safer. Detonation trains manufactured according to this method may be stored in quantity without the final explosive charges which may be quickly and easily placed just before use.

What is claimed is: l. The method of manufacturing a detonation transfer train comprising the steps of;

attaching hollow end pieces to each end of a length of mild detonating fuze; placing a measured charge of compressible explosive material in each hollow end piece; and pressing said charge of explosive into a consolidated mass substantially filling said hollow end pieces; and finally closing and sealing each end piece. 2. Means for pressing an explosive mix into an end piece of an assembled detonation train comprising:

a hinged split die for holding said end piece; stand-off means rabbited on one end to receive said die and having one or more slots to accommodate a trailing end of said detonation train; split adapter means fitting into said die and having inside dimensions contoured to fit a particular end piece; and means securing said split die in closed configuration. 

1. The method of manufacturing a detonation transfer train comprising the steps of; attaching hollow end pieces to each end of a length of mild detonating fuze; placing a measured charge of compressible explosive material in each hollow end piece; and pressing said charge of explosive into a consolidated mass substantially filling said hollow end pieces; and finally closing and sealing each end piece.
 1. The method of manufacturing a detonation transfer train comprising the steps of; attaching hollow end pieces to each end of a length of mild detonating fuze; placing a measured charge of compressible explosive material in each hollow end piece; and pressing said charge of explosive into a consolidated mass substantially filling said hollow end pieces; and finally closing and sealing each end piece. 